England March 1997.

"Like all the best inventions, the Speedseal is so simple that explanations are largely superfluous. The 5mm cover has a machined recess for a nitrile rubber 'O-ring' and is kept in place by three or four knurled thumb screws, depending on pump. Two of the flange holes are slotted, so that only one or two of the remaining thumb screws need to be taken out when replacing the pump impeller. A recess is machined where the impeller touches, exactly the thickness of the now superfluous gasket. Removing the impeller cover can be done literally blindfolded without tools.
Verdict: brilliant"